If you can't remember your password, please enter the email address you used when you signed up, click the "I'm not a robot" box and do what it asks, if anything; you'll see a green tick when it's happy. Finally, click the "Forgotten password?" link above.
You will receive an email with your new password, if it doesn't arrive please check your junk mail folder. Follow the instructions in the email to activate the password and then return to this page to login.